Board members including Pedro Almodóvar, Ken Loach, Mike Leigh and Andrzej Wajda have addressed Russian authorities, calling for a full and fair investigation of allegations against him.

DUBROVNIK, CROATIA -- The Board of the European Film Academy (EFA) has sent a letter to Russian authorities, calling on them to ensure the safety of jailed Ukrainian film director Oleg Sentsov and a thorough and impartial investigation of allegations against him.

"We, [Sentsov's] undersigning European colleagues, are deeply worried and cannot stop wondering how he is and what his future will be," reads the letter, addressed to top Russian officials including President Vladimir Putin and signed by, among others, Pedro Almodóvar, Ken Loach, Mike Leigh, Andrzej Wajda, Wim Wenders and Krzysztof Zanussi.

"In the light of these circumstances, we respectfully call upon you to ensure the safety of Oleg Sentsov; to make public the whereabouts of the detained; to have the detained charged with a recognizable offense or released; to instigate a full, prompt and impartial investigation into the apparently arbitrary detention by the FSB [Russia's Federal Security Service] in order to bring all those responsible to justice," the letter said.

Sentsov was detained in Crimea last month and accused of being a member of Pravy Sektor (Right Sector), a right-wing Ukrainian political group, and plotting a terrorist attack. For more than a week, his whereabouts were unknown. Earlier this month, he was brought to Moscow's Lefortovo jail.

Sentsov's lawyer, Dmitry Dinze, who earlier defended Pussy Riot, said that Sentsov was apparently beaten up and tortured after detention and was subsequently kept away from the public eye to conceal the traces of the beating.

Ukrainian filmmakers and some of their Russian colleagues have repeatedly called for Sentsov's release.

Sentsov was an activist of the pro-European Maidan movement in Kiev but was never known to be associated with the Right Sector. The organization also denied that he is a member.

Sentsov directed the movie Gaamer, which premiered at Rotterdam in 2012, and was developing his next project, Rhino, with financial backing from German regional funding body Medienboard Berlin-Brandenburg.